1. Field of the Invention
This invention relates to catalytic compositions, and more particularly to catalytic compositions which exhibit a marked catalytic effect on the formation of unsaturated nitriles by vapor-phase reaction of an olefin, ammonia and oxygen or an oxygen-containing gas, particularly on the formation of acrylonitrile by vapor-phase reaction of propylene, ammonia and oxygen or an oxygen-containing gas.
2. Description of the Prior Art
Various catalysts have heretofore been proposed for the production of acrylonitrile by vapor-phase catalytic ammoxidation of propylene. It is known in the art that a catalyst comprising molybdenum and bismuth as primary components and further containing iron, phosphorus and the like can be used industrially. Upon further study there is developed a catalyst, for example, comprising molybdenum, bismuth, iron, phosphorus and metallic elements such as nickel and cobalt. However, such a catalyst is not satisfactory in suppressing side reactions, and when such a catalyst is used under the conditions where the gaseous materials are fed into the catalyst bed at a high space velocity and where the conversion of propylene is increased, the selectivity of the catalyst is so decreased that it becomes difficult to achieve a satisfactorily good yield of acrylonitrile. Furthermore, these catalyst are not completely satisfactory with respect to catalyst life.